Heavy rainfall can cause sudden, damaging floods on farmland, yet most small catchments have no stream gauges, making floods hard to predict. We built a detailed computer model that traces how rain becomes runoff across a well-monitored Belgian farm catchment. It reproduces flood timing reasonably well, but less so for short, intense storms. Applied to extreme rainfall scenarios, it pinpoints flood-prone flow paths, a first step toward better flood planning in unmonitored farmland.